Photodetector Array Readout Using Dark Current Balanced Subsets
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Photodetector arrays, particularly those using quantum-dot graphene field-effect transistors (QD GFETs), face challenges in achieving uniform dark current levels across individual photodetectors, leading to variations in signal readouts and requiring complex processing to account for these variations, which complicates image acquisition and amplification.
Innovation Solution
The approach involves identifying and grouping photodetectors into subsets where the combined dark current component is standardized, allowing for the subtraction of dark current from the combined photodetector output signals, thereby isolating the image component and simplifying signal readout and amplification processes using a Bernoulli distribution and multiplexer control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If photodetectors are read out individually to maintain signal accuracy, then measurement precision is improved, but device complexity increases due to required dark current calibration and processing for each photodetector
Solution Approach 1:
Multiple photodetectors are grouped into subsets and read out collectively through shared readout circuits. The output signals from multiple photodetectors are combined and processed together, reducing the number of individual readout channels required while maintaining measurement accuracy through collective dark current subtraction.
Solution Approach 2:
Readout circuits are designed to handle multiple photodetectors simultaneously, making them multi-functional. The same readout circuit can service multiple photodetector subsets, reducing the overall number of readout circuits needed and simplifying the device architecture.
2Measurement precision
If dark current variations are compensated for through individual calibration, then measurement precision is improved, but manufacturing precision requirements increase
Solution Approach 1:
The system performs dark current measurements and uses this information to adjust and compensate for variations. By measuring the actual dark current of each photodetector and using this feedback to correct subsequent measurements, the system achieves high measurement precision without requiring extremely tight manufacturing tolerances.
Solution Approach 2:
The system changes the operational parameters by measuring and adjusting for dark current variations. Instead of requiring uniform dark current at manufacturing, the system adapts to the actual dark current values through calibration and compensation algorithms, relaxing manufacturing precision requirements.
3Productivity
If all photodetectors are read out simultaneously to improve productivity, then productivity is improved, but device complexity increases due to signal processing requirements
Solution Approach 1:
The photodetector array is divided into multiple subsets that are read out in a structured sequence. This segmentation allows the system to process signals from multiple photodetectors efficiently by organizing them into manageable groups, improving productivity while controlling processing complexity through systematic organization.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables efficient image acquisition by standardizing dark current levels across subsets, reducing the complexity of downstream electronics and improving signal-to-noise ratio, allowing for faster and more reliable image formation with reduced variations due to dark current variations.
Implementation Method 1
each photodetector of the array configured to provide a photodetector output signal comprising a dark current component and an image component on exposure to incident electromagnetic radiation from a target scene
Data Source
Figure 1
Figure 2a~2b
Figure 3
AI summary
An apparatus comprising a processor and memory including computer program code, the memory and computer program code configured to, with the processor, enable the apparatus at least to: based on a predetermined dark current component for each photodetector in an array of photodetectors, identify a plurality of subsets of photodetectors from the array for signal readout and amplification by a readout circuit, each photodetector of the array configured to provide a photodetector output signal comprising the dark current component and an image component on exposure to incident electromagnetic radiation from a target scene, wherein each subset of photodetectors is identified such that the combined dark current component of the constituent photodetector output signals for each subset is substantially the same; and provide the identified plurality of subsets for use in signal readout and amplification by the readout circuit.